@CWeeks honestly it depends on how good of shape you are in and how ambitious you are. I shot my bull back in 7 miles. My bull was a 9 year old that added up to a lot of weight. It would have taken me quite a few trips in to get the animal out. There are a few options if you don't have horses:
1. Go in and if you get one tough it out and pack it out in however many trips you need. This would be way hard and take quite a bit of time.
2. Contact someone with horses before hand and if you get one call them and have them come in and help pack it out. You would have to pay them to come help but it's definitely an option.
I would say it would be really tough without horses, in the end they were a lifesaver for our trip.
I hope this helps!